Sulphamic acid prodn. from ammonia and sulphur tri:oxide - by neutralisation and concn. before adding conc. sulphuric acid, increasing yield

摘要

In sulphamic acid (I) prodn. by reacting NH3 with SO3, hydrolysing the reaction mixt. (II) and adding concn. H2SO4 to ppte (I), (II) is neutralised and concn. to reduce the wt. ratio of ammonium sulphate (III) formed as by-prod. (pref. (II) is neutralised to pH 4-6 and conc. to give an ammonium sulphomate concn. of 750-950 g/1). (I) is used for numerous purposes, esp. as weed killer, boiler desealer and flame retardant. The ratio of (III) to (I) is reduced to 5, esp. 3.55, cf. is not 10 in the known process.